Some comments on sections 3.4 and 3.5 of the proposal:
I suspect that the proposed solution will often not make any difference,
since it depends on content authors actually using the dir attribute: I
checked the main page of 4 major Hebrew news sites
http://www.haaretz.co.il/http://www.nrg.co.il/http://news.walla.co.il/
and http://www.ynet.co.il/, and none of them uses dir on either <html>
or <body>
Maybe the proposal should suggest using something similar to dir=auto as
a fallback when no explicit dir attribute is set?
I also have a minor comment on the wording in the sub=section "The
problem" in 3.4.
"On the other hand, pages dare not wrap their LTR dialog text in LRE +
PDF characters for correct display on RTL systems, since most computers
in the world are running an LTR OS without RTL script support turned on,
and thus display LRE and PDF as rectangles."
Firstly, I'm not sure that the premise "most computers in the world are
running an LTR OS without RTL script support turned on" is true today,
so at least I propose changing "most" to "many". Secondly, the sentence
as a whole seems to be a non sequitur. If computers display LRE and PDF
as rectangles, that is more of a font issue than an RTL support issue.
This issue recurs in the sub-section "The problem" in 3.6, but here the
wording is even stronger: "...LTR OS's without RTL support enabled, i.e.
the vast majority of computers."